added scale adjustment to multibar to work with single data point

examples/multiBarChart.html

@@ -43,6 +43,7 @@ text {
 <script>
 
 var test_data = stream_layers(3,10+Math.random()*100,.1).map(function(data, i) {
+//var test_data = stream_layers(3,1,.1).map(function(data, i) { //for testing single data point
   return {
     key: 'Stream' + i,
     values: data

nv.d3.js

@@ -3872,20 +3872,6 @@ nv.models.multiBar = function() {
       var availableWidth = width - margin.left - margin.right,
           availableHeight = height - margin.top - margin.bottom;
 
-      //store old scales if they exist
-      x0 = x0 || x;
-      y0 = y0 || y;
-
-      if (stacked) {
-      //var stackedData = d3.layout.stack()
-        data = d3.layout.stack()
-                     .offset('zero')
-                     .values(function(d){ return d.values })
-                     .y(getY)
-                     (data);
-      }
-
-
 
       //add series index to each data point for reference
       data = data.map(function(series, i) {
@@ -3911,6 +3897,37 @@ nv.models.multiBar = function() {
           .range([availableHeight, 0]);
 
 
+      // If scale's domain don't have a range, slightly adjust to make one... so a chart can show a single data point
+      if (x.domain()[0] === x.domain()[1] || y.domain()[0] === y.domain()[1]) singlePoint = true;
+      if (x.domain()[0] === x.domain()[1])
+        x.domain()[0] ?
+            x.domain([x.domain()[0] - x.domain()[0] * 0.01, x.domain()[1] + x.domain()[1] * 0.01])
+          : x.domain([-1,1]);
+
+      if (y.domain()[0] === y.domain()[1])
+        y.domain()[0] ?
+            y.domain([y.domain()[0] + y.domain()[0] * 0.01, y.domain()[1] - y.domain()[1] * 0.01])
+          : y.domain([-1,1]);
+
+
+      //store old scales if they exist
+      x0 = x0 || x;
+      y0 = y0 || y;
+
+
+
+      if (stacked) {
+      //var stackedData = d3.layout.stack()
+        data = d3.layout.stack()
+                     .offset('zero')
+                     .values(function(d){ return d.values })
+                     .y(getY)
+                     (data);
+      }
+
+
+
+
 
       var wrap = d3.select(this).selectAll('g.wrap.multibar').data([data]);
       var wrapEnter = wrap.enter().append('g').attr('class', 'wrap nvd3 multibar');

src/models/multiBar.js

@@ -35,20 +35,6 @@ nv.models.multiBar = function() {
       var availableWidth = width - margin.left - margin.right,
           availableHeight = height - margin.top - margin.bottom;
 
-      //store old scales if they exist
-      x0 = x0 || x;
-      y0 = y0 || y;
-
-      if (stacked) {
-      //var stackedData = d3.layout.stack()
-        data = d3.layout.stack()
-                     .offset('zero')
-                     .values(function(d){ return d.values })
-                     .y(getY)
-                     (data);
-      }
-
-
 
       //add series index to each data point for reference
       data = data.map(function(series, i) {
@@ -74,6 +60,37 @@ nv.models.multiBar = function() {
           .range([availableHeight, 0]);
 
 
+      // If scale's domain don't have a range, slightly adjust to make one... so a chart can show a single data point
+      if (x.domain()[0] === x.domain()[1] || y.domain()[0] === y.domain()[1]) singlePoint = true;
+      if (x.domain()[0] === x.domain()[1])
+        x.domain()[0] ?
+            x.domain([x.domain()[0] - x.domain()[0] * 0.01, x.domain()[1] + x.domain()[1] * 0.01])
+          : x.domain([-1,1]);
+
+      if (y.domain()[0] === y.domain()[1])
+        y.domain()[0] ?
+            y.domain([y.domain()[0] + y.domain()[0] * 0.01, y.domain()[1] - y.domain()[1] * 0.01])
+          : y.domain([-1,1]);
+
+
+      //store old scales if they exist
+      x0 = x0 || x;
+      y0 = y0 || y;
+
+
+
+      if (stacked) {
+      //var stackedData = d3.layout.stack()
+        data = d3.layout.stack()
+                     .offset('zero')
+                     .values(function(d){ return d.values })
+                     .y(getY)
+                     (data);
+      }
+
+
+
+
 
       var wrap = d3.select(this).selectAll('g.wrap.multibar').data([data]);
       var wrapEnter = wrap.enter().append('g').attr('class', 'wrap nvd3 multibar');